RUI: Exciton-Phonon Interactions in Solids based on Time-Dependent Density Functional Perturbation Theory

RUI：基于瞬态密度泛函微扰理论的固体中激子-声子相互作用

• 批准号: 2105918
• 负责人: Xu Zhang
• 金额: $ 27.75万
• 依托单位: The University Corporation, Northridge
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-11-15 至 2025-10-31
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2105918&HistoricalAwards=false
• 关键词: RUI; Exciton; Phonon; Interactions; Solids

NONTECHNICAL SUMMARYThis award supports computational research and educational activities to advance the understanding of interactions between excited electrons and lattice vibrations in semiconductors and insulators. When an electron is excited to a higher-energy state, it leaves an empty spot with a positive charge known as a hole. The electron and the hole can be strongly bound to each other in an excitonic state. The interactions between phonons (quantization of lattice vibrations) and excitons play a crucial role in many chemical and materials problems. The goal of this research is to develop an accurate, versatile, and efficient first-principles approach to compute exciton-phonon interactions in extended and condensed-matter systems. The method will have applications in energy conversion and storage, ranging from photovoltaics to photocatalysis, photodetectors, photo-synthesis, optoelectronics, light-emitting diodes, and biosensors. In this project, the PI will apply the method to study the exciton-phonon interactions in two-dimensional van der Waals heterostructures, which are the new frontier for novel optoelectronic and photovoltaic device applications.The project will also provide cutting-edge educational and training opportunities to undergraduate and graduate students as well as postdoctoral scholars, who will gain valuable experience in computational materials science. The PI is fully committed to broadening participation and enhancing diversity in materials research and education by strengthening opportunities for underrepresented groups. A graduate course on the first-principles method will be developed to prepare the students for the research activities. The PI will also reach out to local high schools and community colleges through targeted recruitment, workshops, summer camps for high-school teachers, and curriculum development in community colleges.TECHNICAL SUMMARYThis award supports computational research and educational activities to develop a novel computational methodology for the study of coupled electron-ion dynamics with electronic excited states in semiconductors and insulators. Understanding, predicting, and ultimately controlling exciton behavior and coupled exciton-ion dynamics are central to diverse chemical and materials problems. Accurate and efficient first-principles methods are highly desired for quantitatively computing exciton-phonon interactions in real materials applications. The project goal is to develop an accurate, efficient, and robust first-principles approach to capture exciton-phonon interactions in semiconductors and insulators based on time-dependent density functional perturbation theory. The method developed will allow calculations of the exciton band structure, charge density, and ionic forces associated with the exciton state, non-adiabatic couplings between exciton states, the exciton-phonon coupling matrix, and exciton dynamical processes in extended solid systems. Fully unconstrained noncollinear magnetism will be implemented to determine excitonic properties in materials with a prominent spin-orbital coupling effect. Several levels of parallelization will be exploited, rendering computational codes amenable to massively parallel platforms. In this project, the method will be used to study the phonon-assisted interfacial charge and energy transfer in two-dimensional transition-metal dichalcogenide-based van der Waals heterostructures, unraveling the momentum transfer between excitons and phonons as well as intra/interlayer exciton-phonon interactions during interfacial exciton dynamics.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

非技术摘要这一奖项支持计算研究和教育活动，以促进对半导体和绝缘体中激发电子与晶格振动之间相互作用的理解。当电子对更高能量状态感到兴奋时，它留下了一个空位，带有正电荷称为孔。电子和孔可以在激子状态下彼此牢固地结合。声子（量化晶格振动的量化）和激子之间的相互作用在许多化学和材料问题中起着至关重要的作用。这项研究的目的是开发一种准确，多功能，高效的第一原理方法，以计算扩展和凝结的系统中的激子 - phonon相互作用。该方法将在能量转化和存储中应用，从光伏到光催化，光电探测器，照片合成，光电子，光发射二极管和生物传感器。在该项目中，PI将采用这种方法来研究二维范德华的异质结构中的激子 - 光子相互作用，这是新型的光电和光伏设备应用的新领域。该项目还将为未成年人以及研究生级别的材料提供尖端的教育和培训机会，并获得了材料，该材料有价值的经验，即有价值的材料，即有价值的材料，该培训将获得有价值的经验。 PI通过加强代表性不足的群体的机会来扩大参与并增强材料研究和教育的多样性。将开发有关第一原理方法的研究生课程，以便为学生准备研究活动。 PI还将通过有针对性的招聘，研讨会，高级教师的夏令营以及社区大学的课程开发来接触当地的中学和社区大学。技术摘要奖支持计算研究和教育活动，以开发一种新型的计算方法，用于与Electron-Ion激发型状态和Indicultors和Instericscultors and Instoctortors and Instonics and Instorictors and Instorys and Indicultors一起研究。理解，预测并最终控制激子行为以及耦合的激子离子动力学对于多种化学和材料问题至关重要。精确有效的第一原理方法非常需要定量计算真实材料应用中的激子相互作用。项目目标是基于时间依赖性密度功能扰动理论，开发一种准确，高效且健壮的第一原理方法，以捕获半导体和绝缘子中的激子相互作用。开发的方法将允许计算与激子状态，激子状态之间的非绝热耦合相关的激子结构，电荷密度和离子力，在扩展的固体系统中，激子状态之间的非绝热耦合，激子 - phonon耦合矩阵和激子动力学过程。将实施完全不受限制的非共线磁性，以确定具有突出旋转轨道耦合效果的材料中的激子特性。将利用几个级别的并行化，从而使计算代码适合大规模并行平台。 In this project, the method will be used to study the phonon-assisted interfacial charge and energy transfer in two-dimensional transition-metal dichalcogenide-based van der Waals heterostructures, unraveling the momentum transfer between excitons and phonons as well as intra/interlayer exciton-phonon interactions during interfacial exciton dynamics.This award reflects NSF's statutory mission and has been deemed worthy通过使用基金会的知识分子和更广泛影响的评论标准来通过评估来支持。

项目成果

Exciton dispersion and exciton–phonon interaction in solids by time-dependent density functional theory

固体中激子色散和激子与声子相互作用的时间相关密度泛函理论

• DOI: 10.1063/5.0137326
• 发表时间: 2023
• 期刊: The Journal of Chemical Physics
• 作者: Liu, Junyi;Lu, Gang;Zhang, Xu
• 通讯作者: Zhang, Xu